[Mesa-dev] stack overflow in gluEndSurface

[Raymond Maple]

Hello,
    I have run into a problem with gluNurbs that I would appreciate some
help with.  I am attempting to render trimmed NURBS surfaces read from an
IGES file.  The first few surfaces seem to render OK, but after some number,
say N, I start getting a GL_STACK_OVERFLOW error with the call to
gluEndSurface.  If I render any single trimmed surface, it works fine, so I
don't think its the NURBS data.  Also, if I render just the untrimmed
surface, everything is fine, which points to something in the trimming code.
  I've checked the depth of the modelview, projection, and texture matrix
stacks before and after the glEndSurface call, and they are all what I
expect them to be (1 or 2), so the error must be thrown by something in the
glu nurbs tesselator.  I've searched through the glu code, but haven't found
anywhere that the matrix stacks are manipulated, or where GL_STACK_OVERFLOW
is thrown, though I did see where it is included in libutil/error.cc  If
anyone could shed some light on what might be going on, I'd appreciate it.
Additional data:
Problem seen with GLU libraries shipped with Ubuntu 9.04 and RHEL 5.4 (not
sure of versions)
Nvidia drivers & core OpenGL
pyOpenGL 3.0/3.1
All surfaces and trim curves are non-rational BSplines
I'm rendering using object space sampling, but have same error with default
pixel sampling
Onset of error seems to depend on sampling size, but once one surface has a
problem, all following surfaces do.

Thanks
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